U.S. Pat. No. 6,167,335 discloses a system for measuring the dimensions of particles. The system is an automatic inspection device allowing microscopic dimensions, such as the area, diameter, height, and line width of defects and lines of a photographic mask to be measured. It is, however, not a coordinate measuring machine for determining the positions of structures relative to a coordinate system of the coordinate measuring machine.
U.S. Pat. No. 5,825,483 discloses a plate for calibrating the angle of vision. This plate is used in the manufacture of semiconductors. The plate is not suitable, however, for measuring positions of structures on a substrate.
U.S. Patent Application No. 2006/0277521 A1 discloses a method of lithography referred to as double exposure. Measurement of the positions of structures for double exposure is not envisaged.
In the article by William BROADBEN, et. al. “Results from a new die-to-die database reticle inspection platform” in proceedings of SPIE Vol. 6518 Metrology Inspection, and Process Control for Microlithography XXI, 651821, 10 pages, April 2007, there is no reference to the determination of the positions of structures on the surface of a mask.
German Patent Application DE 102 57 323 A1 discloses a method and a microscope for detecting images of an object. This only refers to issues of evaluation arising when line arrays, for example, are imaged.
A coordinate measuring machine for measuring structures on wafers and masks used for their manufacture is known from the presentation paper “Pattern Placement Metrology for Mask Making” by Dr. Carola Bläsing. The paper was held at the Semicon Education Program Convention in Geneva on Mar. 31, 1998. The description given there is the basis for a coordinate measuring machine of which various models are commercially available.
Further, a coordinate measuring machine is known from a plurality of patent applications, such as DE 19949005, DE 19858428, DE 10106699 or DE 102004023739. In all documents from the state of the art a coordinate measuring machine is disclosed allowing structures to be measured on a substrate. Herein, the substrate is placed on a measuring stage traversable in the X coordinate direction and Y coordinate direction. The coordinate measuring machine is configured in such a way that the positions of structures, such as the edges of structures, can be determined by means of an objective. For determining the positions of structures, or their edges, it is necessary to determine the position of the measuring stage by means of at least one interferometer. Finally the position of the edge is determined in relation to a coordinate system of the measuring machine.